A product can be fully designed, certified and tooled — and still not ship, because one microcontroller or power IC has a lead time of many months. Shortages and sudden end-of-life notices hit small and medium volume customers hardest, since allocation favours the largest buyers. Most of this risk is set at design time, which is also when it is cheapest to reduce.
1. Review lifecycle and sourcing before layout
| Status / risk | Meaning | Action |
|---|---|---|
| Active | In production, recommended | Preferred choice |
| NRND (not recommended for new designs) | Still made, but on the way out | Avoid in new designs |
| EOL / last-time buy announced | Production ending | Replace now, or plan a last-time buy |
| Single source | Only one manufacturer makes a compatible part | Find alternates or accept the risk knowingly |
| Long or volatile lead time | Allocation-prone (often MCUs, power, memory, some passives in specific sizes) | Order early, hold buffer stock |
2. Design for alternates
- Approved alternates for every non-critical part, written into the BOM so the assembler can substitute without asking.
- Common packages and values: standard passive sizes and values have many sources; exotic ones do not.
- Footprints that accept more than one part, e.g. pin-compatible regulators or dual footprints for critical ICs.
- MCU families with several memory sizes or package options in the same footprint.
- Firmware that abstracts hardware where practical, so switching a sensor or MCU variant does not mean rewriting everything.
3. Buy from the right channels
Authorized distributors and manufacturers are the safest source. Brokers and the open market can fill gaps during shortages, but carry real counterfeit and handling risk — require traceability documents and incoming inspection for such parts, and get the customer’s approval before using them.
4. Plan stock, not just design
- Hold buffer stock of long-lead or single-source parts for the next builds.
- Place long-lead orders before the PCB is final when the part choice is stable.
- Watch for end-of-life notices and decide early between redesign and last-time buy.
- Agree with your assembler who buys, owns and stores critical components.
5. Make the BOM say what you mean
A BOM with manufacturer part numbers, alternates and “no substitution” flags lets the assembler act quickly when stock disappears. See the PCB assembly files checklist, our PCB assembly capability, or send your BOM for an availability and lifecycle review.